1. Technical Field
The present invention relates generally to integrated circuit chip testing, and particularly to an improved functional and stress testing apparatus.
2. Description of Related Art
High performance processor chips are frequently sorted by various high performance metrics so they can be matched with the class of machine for which they are intended. This typically involves investigating chip performance using functional test sequences at the extremes of various operational windows for several variables, among these being chip voltage, clock speed, power, and temperature. These test sequences at temperature extremes can also identify early life failures and reduce the likelihood of a faulty chip escaping and being assembled into high-function and high-cost devices.
Processor chips are typically attached to a temporary carrier (e.g., a temporary chip attach, or TCA) and then installed in a device tester. The tester controls the applied voltage, the clock frequency, the chip test sequences and power, and the chip temperature. Tester architectures vary significantly, but primary components typically include a test board that is compatible with the class of device to be tested, a control computer to control the test sequence, programmable power sources, other control hardware to control delivery of test resources (voltage, current, pneumatics, coolant fluid, etc.), a chiller to deliver a coolant fluid to the device being tested, network interface and communication hardware and software, and a test nest. The nest is that portion of the tester that physically accommodates the device under test (DUT).
Previous test apparatus suffered from shortcomings, such as the inability to accurately and repeatedly register the coldplate with respect to the TCA chip surface, which can contribute to chip damage. Further, the external loads applied to the coldplate were not well balanced, resulting in a poorly centered contact load between the coldplate and chip surface, which detracts from the thermal control performance of the assembly.
These and other issues are addressed by the present invention.